Epilepsias en las malformaciones del desarrollo cortical / Malformations of cortical development and epilepsy

Alrededor del 15% de las epilepsias en pediatría son fármaco-resistentes y en el 40% de este grupo la etiología es una malformación del desarrollo cortical (MDC). El esquema de clasificación actual de las MDC se basa en las etapas primarias de desarrollo de la proliferación celular, migración neuronal y organización cortical. Teniendo en cuenta la clínica y las alteraciones moleculares, se propuso una clasificación basada en la disrupción de las vías principales y el fenotipo neurorradiológico. Se dividió a las MDC en cuatro grupos: la megalencefalia y las displasias corticales focales; las tubulinopatías y lisencefalias; el espectro de las polimicrogirias y las heterotopías. Hasta el momento, más de 100 genes han sido asociados con uno o más tipos de MDC. Los mecanismos biológicos y genéticos incluyen la regulación del ciclo celular en varios estadios, división celular), apoptosis, diferenciación celular, función y estructura del citoesqueleto, migración neuronal y membrana basal. El espectro de síndromes epilépticos asociados con las MDC es amplio e incluye desde encefalopatías epilépticas de comienzo temprano a epilepsias focales de debut más tardío. Teniendo en cuenta que la evolución de la epilepsia hacia la refractariedad en las MDC es importante, el diagnóstico precoz y la elección de la mejor opción terapéutica influirán en el pronóstico de los pacientes.

Around 15% of childhood epilepsies are resistant to antiepileptic drugs, 40% of which are caused by malformations of cortical development (MCD). The current classification scheme for MCD is based on the primary developmental steps of cell proliferation, neuronal migration, and cortical organization. Considering the clinic and molecular alterations, a classification based on main pathways disruption and imaging phenotype has been proposed. MCD were divided into four groups: megalencephaly and focal cerebral dysplasia; tubulinopathies and lissencephalies; polymicrogyria syndromes and heterotopia syndromes. More than 100 genes have been reported to be associated with different types of MCD. Genetic and biological mechanisms include different stages of cell cycle regulation - especially cell division -, apoptosis, cell-fate specification, cytoskeletal structure and function, neuronal migration, and basement-membrane function. The associated epileptic syndromes are varied ranging from early-onset epileptic encephalopathies to focal epilepsies. As MCD are common causes of refractory epilepsy, a prompt diagnosis and the development of different therapeutic options in order to improve the outcome of the patients are essential.

Partial epilepsy: A pictorial review of 3 TESLA magnetic resonance imaging features

Epilepsy is a disease with serious consequences for patients and society. In many cases seizures are sufficiently disabling to justify surgical evaluation. In this context, Magnetic Resonance Imaging (MRI) is one of the most valuable tools for the preoperative localization of epileptogenic foci. Because these lesions show a large variety of presentations (including subtle imaging characteristics), their analysis requires careful and systematic interpretation of MRI data. Several studies have shown that 3 Tesla (T) MRI provides a better image quality than 1.5 T MRI regarding the detection and characterization of structural lesions, indicating that high-field-strength imaging should be considered for patients with intractable epilepsy who might benefit from surgery. Likewise, advanced MRI postprocessing and quantitative analysis techniques such as thickness and volume measurements of cortical gray matter have emerged and in the near future, these techniques will routinely enable more precise evaluations of such patients. Finally, the familiarity with radiologic findings of the potential epileptogenic substrates in association with combined use of higher field strengths (3 T, 7 T, and greater) and new quantitative analytical post-processing techniques will lead to improvements regarding the clinical imaging of these patients. We present a pictorial review of the major pathologies related to partial epilepsy, highlighting the key findings of 3 T MRI.

Mapeo del lenguaje utilizando estimulación magnética transcraneal repetitiva por navegación: un estudio comparativo con la estimulación cortical directa intraoperatoria / Language mapping using repetitive transcranial magnetic stimulation by navigation: a comparative study with direct intraoperative cortical stimulation

Introducción: la estimulación cortical directa (DCS) es una metodología corrientemente usada para localizar áreas del lenguaje en intervenciones quirúrgicas que incluyan resecciones.La estimulación magnética transcraneana repetitiva (rTMS) a demostrado también su capacidad para inducir alteraciones transitorias. Recientemente el desarrollo del Sistema de Navegación de TMS asegura precisa localización del sitio estimulado. El objetivo del trabajo es estudiar la confiabilidad de la estimulación magnética transcraneal repetitiva navegada (nrTMS) en la localización de los sitios del lenguaje. Métodos: Once pacientes seleccionados para mapeo del lenguaje por DCS fueron evaluados pre-cirugía con nrTMS. Los mapeos de lenguaje prequirúrgicos mediante nrTMS fueron comparados con DCS. Resultados: Un total de 25 nrTMS sitios del lenguaje y 38 DCS fueron localizados. La sensibilidad y la especificidad obtenida fue de 88.4 y 95.6, respectivamente. La distancia media fue evaluada en 4,5mm. Conclusiones: Los dispositivos de nrTMS permiten la identificación de las áreas corticales del lenguaje. Con un alto grado de concordancia con el mapeo TMS. La nrTMS se muestra como una herramienta de interés en la investigación y aplicación práctica en la función del lenguaje.

Introduction: direct cortical stimulation (DCS) is currently used to localise language areas in surgical resections. Repetitive transcranial magnetic stimulation (rTMS) has also shown its capacity to induce transient language alterations. Newly developed Navigated Brain Systems of TMS ensure precise topographical localisation of the stimulated site. The objective was to study the reliability of navigated repetitive transcranial magnetic stimulation (nrTMS) in language sites localisation.Methods: Eleven patients selected for DCS language mapping were presurgically evaluated with nrTMS. These presurgicalnrTMS language maps were then compared with DCS.Results: A total number of 25 nrTMS and 38 DCS language sites were localised. Sensitivity and specificity were calculated as 88.4 and 95.6 respectively. Mean distance was assessed as 4.5 millimetres. Conclusions: nrTMS devices allow identification of cortical language areas, with a high degree of concordance to TMS mapping. NrTMS shows up as an interesting tool for research and practical application in language function.

Trastornos de la migración neuronal: un caso de lisencefalia / Neuronal migration disorders: a lissencephaly case

Las malformaciones del desarrollo cortical originan un grupo de patologías, que cursan con diversas manifestaciones las cuales marcan un grado de minusvalía significativo en quienes las padecen. La Lisencefalia es una de las alteraciones de la migración neuronal caracterizada por una corteza cerebral de superficie lisa o con pocas circunvoluciones. Este trastorno está frecuentemente asociado a epilepsias de difícil manejo. Se presenta el caso de un paciente masculino de 18 meses de edad con diagnóstico de Lisencefalia quien cursa con convulsiones tónicas generalizadas desde los 8 meses de edad. Se le realizó TAC de cráneo simple y resonancia magnética de cerebro para confirmar el diagnóstico y se dio manejo farmacológico a las convulsiones.

Malformations of cortical development originate a group of pathologies that involve diverse manifestations that mark a significant degree of disability in those who suffer from. The Lissencephaly is one of alterations in neuronal migration characterized by a smooth surface or with few convolutions in the cerebral cortex. This disorder is often associated with difficult management Epilepsies. We report the case of a male patient from 18 months of age with a diagnosis of Lissencephaly, who presents generalized tonic seizures from 8 months of age. Was performed a simple skull CT and brain magnetic resonance to confirm the diagnosis and the pharmacological management was given to seizures.

Investigation of magnetic resonance imaging texture analysis as an aid tool for characterization of refractory epilepsies / Investigacao da analise de textura em imagem de ressonancia magnetica como auxilio para caracterizacao de epilepsias refratarias

Refractory epilepsies are syndromes for which therapies that employ two or more antiepileptic drugs, separately or in association, do not result in control of crisis. Patients may present focal cortical dysplasia or diffuse dysplasia and/or hippocampal atrophic alterations that may not be detectable by a simple visual analysis in magnetic resonance imaging. The aim of this study was to evaluate MRI texture in regions of interest located in the hippocampi, limbic association cortex and prefrontal cortex of 20 patients with refractory epilepsy and to compare them with the same areas in 20 healthy individuals, in order to find out if the texture parameters could be related to the presence of the disease. Of the 11 texture parameters calculated, three indicated the existence of statistically significant differences between the studied groups. Such findings suggest the possibility of this technique contributing to studies of refractory epilepsies.

Epilepsias refratárias compreendem síndromes para as quais as terapias que empregam duas ou mais drogas antiepilépticas, isoladamente ou em associação, não resultam no controle da frequência das crises. Portadores podem apresentar displasias corticais focais ou difusas e/ou alterações atróficas hipocampais que, em alguns casos, não são detectáveis por uma simples análise visual nas imagens de ressonância magnética. Nesse contexto, o objetivo deste estudo foi avaliar a textura de imagens de RM em regiões de interesse localizadas nos hipocampos, córtex de associação límbico e córtex pré-frontal de 20 pacientes com epilepsia refratária e compará-las às mesmas áreas de um grupo de 20 indivíduos sadios. Dos 11 parâmetros de textura calculados, três indicaram a existência de diferenças estatisticamente significantes entre os grupos estudados. Tais achados sugerem a possibilidade desta técnica contribuir para os estudos das epilepsias de difícil controle.

Evaluación de la conectividad cerebral mediante teoría de grafos / Cerebral Connectivity Analysis Using Graph Theory

Introducción: Las últimas técnicas de análisis de RM funcional permiten medir el cambio espontáneo de la señal BOLD en reposo. Los métodos de análisis derivados de estos estudios se dividen en: mapas de conectividad funcional y conectividad cerebral por grafos. Un grafo permite representar cualquier sistema compuesto de elementos interconectados. Este enfoque es, en teoría, aplicable a cualquier escala, modalidad o cantidad de información neurocientífica. Objetivo: Presentar los resultados de la implementación de un algoritmo para analizar la conectividad funcional por teoría de grafos. Materiales: Resonador de 1,5 T para obtener imágenes con información en T1 volumétricas, para capturar la información estructural, y EPI con información en T2, para capturar la señal BOLD en reposo, de 19 individuos sanos y 1 paciente con epilepsia con diagnóstico imaginológico de displasia cortical. Se les solicitó permanecer despiertos, con los ojos cerrados, evitando pensar en algo particular. Los estudios fueron preprocesados y luego analizados mediante un grafo construido a partir de 8196 vóxeles de la corteza cerebral. Resultados: El enfoque permite obtener imágenes que codifican el patrón de correlación que tiene la señal BOLD en un vóxel con todos los otros vóxeles en la corteza cerebral. Este enfoque es replicable. Conclusiones: Se ha presentado un enfoque para analizar la conectividad funcional por teoría de grafos que permite cuantificar el grado de correlación de la señal BOLD en una muestra de vóxeles de la corteza cerebral y se ha presentado cómo cambia el patrón de correlación en un caso de epilepsia del lóbulo frontal.

Introduction: The latest analysis techniques of functional magnetic resonance enable to measure the spontaneous change of the BOLD signal during rest periods. The analysis and presentation methods which derive from the information obtained from these studies are divided in two approaches: functional connectivity at rest and functional connectivity using graph theory. A graph enables the representation of any system composed of interconnected elements. This approach is applicable to any scale, modality or quantity of neuroscientific data. Objective: To present the results of the implementation of one algorithm for the analysis of functional connectivity using graph theory. Materials and methods: The use of a 1.5 T magnetic resonator to obtain T1 volumetric images, in order to capture the structural information and the use of EPI with information in T2 in order to capture the BOLD signal at rest, in 19 healthy patients and 1 patient with epilepsy with a imaging diagnosis of cortical dysplasia. The patients were awake during the acquisition. Their eyes were closed, and they avoided specific thoughts. The studies are preprocessed using the approach reported in the literature and are analyzed with graphs using 8196 points of the cerebral cortex. Results: The presented approach enables to obtain images which encode the correlation pattern in the BOLD signal in a single. Meanwhile,the other voxels are in the cerebral cortex. This approach is replicable with other patients. Conclusions: An approach has been presented in order to analyze functional connectivity using graph theory. This enables to quantify the degree of correlation of a BOLD signal, in a voxel sample from the cerebral cortex. This approach also indicates how the correlation pattern changes in case of frontal lobe epilepsy.

Surgical and postmortem pathology studies: contribution for the investigation of temporal lobe epilepsy / Patologia cirúrgica e post mortem: contribuição para a investigação da epilepsia do lobo temporal

Pathology studies in epilepsy patients bring useful information for comprehending the physiopathology of various forms of epilepsy, as well as aspects related to response to treatment and long-term prognosis. These studies are usually restricted to surgical specimens obtained from patients with refractory focal epilepsies. Therefore, most of them pertain to temporal lobe epilepsy (TLE) with mesial temporal sclerosis (MTS) and malformations of cortical development (MCD), thus providing information of a selected group of patients and restricted regions of the brain. Postmortem whole brain studies are rarely performed in epilepsy patients, however they may provide extensive information on brain pathology, allowing the analysis of areas beyond the putative epileptogenic zone. In this article, we reviewed pathology studies performed in epilepsy patients with emphasis on neuropathological findings in TLE with MTS and MCD. Furthermore, we reviewed data from postmortem studies and discussed the importance of performing these studies in epilepsy populations.

Estudos de patologia em pacientes com epilepsia trazem informações úteis para compreender a fisiopatologia de várias formas de epilepsia, bem como aspectos relacionados ao tratamento e ao prognóstico a longo prazo. Esses estudos são usualmente restritos a espécimes cirúrgicos obtidos de pacientes com epilepsias focais refratárias. Portanto, a maioria diz respeito à epilepsia do lobo temporal (ELT) com esclerose mesial temporal (EMT) e às malformações do desenvolvimento cortical (MDC). Desse modo, fornecem informações sobre um grupo selecionado de pacientes e sobre regiões restritas do cérebro. Raramente são realizados estudos post mortem do cérebro inteiro em pacientes com epilepsia; entretanto, eles podem prover informações relevantes sobre patologia cerebral, permitindo a análise de áreas além da zona epileptogênica putativa. Neste artigo, foram revisados estudos de patologia feitos em pacientes com epilepsia, com ênfase nos achados neuropatológicos em ELT com EMT e MDC. Foram revisados, ainda, dados de estudos post mortem e discutiu-se a importância da realização desses estudos em populações de pessoas com epilepsia.

Malformations of cortical development: current concepts and advanced neuroimaging review / Malformações do desenvolvimento cortical: conceitos atuais e revisão de neuro-imagem avançada

Malformations of cortical development (MCD) result from disruptions in the complex process of the human brain cortex formation and are highly associated to severe epilepsy, neurodevelopmental delay and motor dysfunction. Nowadays, magnetic resonance imaging (MRI) is the cornerstone of the work-up of patients with epilepsy and modern advanced imaging techniques have improved not only our ability to detect and characterize cortical malformations, but also in identifying associated functional abnormalities that are far beyond the structural visualized lesions. Herein, we address the most currently used classifications of MCD and make a concise review of the embryological process of cortical development. Our main goal is to summarize recent advances and new trends in diagnostic imaging techniques concerning MCD. Thereafter, follows a brief discussion of specific disorders and their radiological features.

As malformações do desenvolvimento cortical (MDC) resultam de distúrbios no complexo processo do desenvolvimento do córtex cerebral humano e estão comumente associadas a epilepsia severa e disfunções neuropsicomotoras. Atualmente, as imagens por ressonância magnética (RM) são a pedra angular no manejo de pacientes com epilepsia e modernas técnicas avançadas de imagem melhoraram não só a nossa capacidade de detectar e caracterizar as malformações corticais, mas também levaram ao reconhecimento de anomalias funcionais associadas que estão muito além das lesões estruturais visibilizadas. Abordaremos as classificações mais utilizadas de MDC e revisaremos a embriologia do desenvolvimento cortical. Nosso principal objetivo é destacar os avanços recentes e as novas tendências em técnicas de diagnóstico por imagens relacionadas às MDC. Em seguida, faremos uma breve discussão sobre alguns transtornos específicos e suas características radiológicas.

Avaliação da arquitetura do sono em crianças com epilepsia refratária / Evaluation of sleep architecture in children with refractory epilepsy

INTRODUÇÃO: Há um interesse crescente nas relações entre sono e epilepsia incentivado pela compreensão de que existem interações potencialmente relevantes nas duas direções. Embora o papel do sono na hipersincronização e a crescente preocupação na geração de crises sejam bem conhecidos, o grau no qual o sono pode facilitar ou induzir a um fenômeno epileptogênico, nas epilepsias lesionais, permanece indefinido. As epilepsias lesionais parecem apresentar um mecanismo particular de epileptogenicidade e o esclarecimento do papel da macro e microarquitetura do sono pode auxiliar na antecipação e monitorização de fenômenos epilépticos relacionados ao sono, conforme a etiologia da epilepsia. OBJETIVO: revisar e discutir as relações entre sono e epilepsia na infância e adolescência relacionando as alterações estruturais do sono à etiologia da epilepsia. MÉTODOS: revi-são bibliográfica utilizando o banco de dados Medline, abrangendo os estudos publicados nos últimos quinze anos, com as palavras-chave (unitermos) sono e epilepsia. CONCLUSÕES: epilepsia refratária durante a infância parece influenciar a organização do sono principalmente naqueles pacientes com etiologia lesional. A definição do tipo de epilepsia pode ser importante na antecipação dos distúrbios de sono nesta população.

ABSTRACT INTRODUCTION: There has been a growing interest in the relations between sleep and epilepsy, kindled by the realization that there are many potentially relevant two-way interactions. Even though the hyper-synchronizing role of sleep and its attending increase in the probability of seizure generation are well known, the degree to which sleep may facilitate or induce epileptogenic phenomena in lesional epilepsies remains unclear. The lesional epilepsies seems to have intrinsic epileptogenic properties and the knowledge about sleep macro and microarchiteture could help clinician to anticipate and monitor sleep-related epileptic phenomena according to the etiology of the epilepsy OBJECTIVE: Discuss the relationship between sleep and epilepsy in childhood and adolescence. METHODS: Literature review in journals indexed through Medline, from the last 15 years. CONCLUSION: Refractory epilepsy during childhood influences sleep organization mainly in patients with lesional etiology. The definition of the type of epilepsy is important to anticipate sleep disorders in this population.

Processamento temporal auditivo: relação com dislexia do desenvolvimento e malformação cortical / Temporal auditory processing: correlation with developmental dyslexia and cortical malformation

TEMA: processamento temporal auditivo e dislexia do desenvolvimento. OBJETIVO: caracterizar o processamento temporal auditivo em escolares com dislexia do desenvolvimento e correlacionar com malformação cortical. MÉTODO: foram avaliados 20 escolares, com idade entre 8 e 14 anos, divididos em grupo experimental (GE) composto por 11 escolares (oito do gênero masculino) com o diagnóstico de dislexia do desenvolvimento e grupo controle (GC) composto por nove escolares (seis do gênero masculino) sem alterações neuropsicolinguísticas. Após avaliações neurológica, neuropsicológica e fonoaudiológica (avaliação de linguagem e leitura e escrita) para obtenção do diagnóstico, os escolares foram submetidos à avaliação audiológica periférica e posteriormente aplicou-se o teste Random Gap Detection Test e/ou Random Gap Detection Test Expanded. RESULTADOS: observou-se diferença estatisticamente significante entre os escolares do GE e GC, com pior desempenho para o GE. A maioria dos escolares do GE apresentou polimicrogiria perisylviana. CONCLUSÃO: escolares com dislexia do desenvolvimento podem apresentar alterações no processamento temporal auditivo com prejuízo no processamento fonológico. Malformação do desenvolvimento cortical pode ser o substrato anatômico dos distúrbios.

BACKGROUND: temporal auditory processing and developmental dyslexia. AIM: to characterize the temporal auditory processing in children with developmental dyslexia and to correlate findings with cortical malformations. METHOD: twenty school-aged children, ranging in age from 8 to 14 years were evaluated. These children were divided into two groups: the experimental group (EG) was composed by 11 children (eight were male) with developmental dyslexia and the control group (CG) was composed by nine normal children (six were male). After neurological assessment and verification of the intellectual level, language, reading and writing skills in order to determine the diagnosis, children underwent a peripheral audiological evaluation and Random Gap Detection Test and/or Random Gap Detection Test Expanded. RESULTS: a statistically significant difference between children in the EG and CG were observed, with children in the EG presenting worst performances. Most of the children in the EG presented perisylvian polymicrogyria. CONCLUSION: children with developmental dyslexia may present temporal auditory processing disorders with deficits in phonological processing. Cortical malformations may be the anatomical substrate of these disorders.

Patología de las malformaciones del desarrollo cortical en pacientes con epilepsia refractaria: experiencia en un hospital pediátrico / Pathology of CDM in patients with refractory epilepsy: experience in a pediatric hospital

Las malformaciones del desarrollo cortical (MDC) comprenden un grupo heterogéneo de lesiones caracterizadas por una desorganización de la arquitectura normal de la corteza cerebral, que incluye desde cambios microscópicos sutiles a extensas lesiones que pueden comprometer un hemisferio entero o conformar síndromes genéticos definidos. Múltiples esquemas de clasificación han sido propuestos para catalogar pacientes con malformaciones del desarrollo en subgrupos, basados en criterios de imágenes y hallazgos patológicos. Sin embargo aun hoy, la bibliografía es muy confusa en cuanto a su nomenclatura y/o a los criterios utilizados para evaluar la reproducibilidad. En algunos casos puede ser difícil distinguir estas lesiones de un tumor (ganglioglioma o Tumor Neuroepitelial Disembrioplásico) por la posible coexistencia de ambas lesiones y la representatividad de las muestras. La utilización del tejido humano de las resecciones quirúrgicas provee una fundamental herramienta tanto para esclarecer la patogénesis como para futuras investigaciones. Nuestra experiencia en patología de la epilepsia relacionada con malformaciones del desarrollo a lo largo de 20 años en un hospital público pediátrico incluye patología del lóbulo temporal y extratemporal, con lesiones puras malformativas, patología dual y otras asociaciones.

Malformations of cortical development (MCD) comprise a heterogeneousgroup of lesions characterized by a disruption of the normal architecture of the cerebral cortex, ranging from subtlemicroscopic lesions to large lesions that can compromise an entire hemisphere or shape defined genetic syndromes. Multiple classification schemes have been proposed to catalogue patients with developmental malformations in subgroups based on criteria and pathological images. But even now, literature is very confusing in their classification and / or the criteria used to assess reproducibility. In some cases it may be difficult to distinguish these lesions from a tumor (ganglioglioma orDysembryoplastic Neuroepithelial Tumor) for the possible coexistenceof both lesions and representativeness of the samples. The use of human tissue for surgical resection provides afundamental tool both to clarify the pathogenesis and for future research. Our experience in pathology of epilepsy associated with malformations of the development over 20 years in a public pediatric hospital includes temporal lobe and extratemporal pathology, pure malformations, dual pathology and other associations.

Áreas corticales elocuentes: estudio con RMF bases fisiológicas, procedimiento y aplicaciones clínicas / Eloquent cortical areas: RMF study physiological bases, procedures and clinical applications

El conocimiento de la anatomía funcional del cerebro es útil para correlacionar síntomas específicos con la localización de lesiones en áreas específicas. La RM funcional es una herramienta diagnóstica no invasiva que permite estudiar funciones cerebrales en base a una técnica denominada BOLD (blood oxygenation level dependent). Si bien la principal indicación de la RMf corresponde a la evaluación prequirúrgica de tumores cerebrales, esta metodología diagnóstica también es útil, entre otras aplicaciones, para el estudio de la lateralización del lenguaje, de la memoria y de la neuroplasticidad como mecanismo compensador de daño cerebral de origen traumático o vascular.

The knowledge of the brain functional anatomy is useful to link specific symptoms with the lesion´s location in specific areas. Functional MRI is a non-invasive diagnostic tool able to visualize brain function with a technique named BOLD(blood oxygenation level dependent). The most important indication of fMRI is for presurgical planning in patients with brain tumors, moreover this technique can use to study language lateralization, memoryand neuroplasticity, among other functions.

Relación entre electroencefalograma y neuroimagen en niños con epilepsia focal de difícil control / Relation between electroencephalogram and neuroimaging present in children with epilepsy of difficult control

Las epilepsias focales son las màs frecuentes en los niños, y la resistencia al tratamiento farmacológico puede estar presente hasta en el 30 por ciento de los pacientes. Se realizó este estudio con el objetivo de dirigir la atención hacia la coincidencia topográfica de los paroxismos electroencefalográficos, con lesiones estructurales demostrables por neuroimagen, para facilitar el diseño de estrategias terapéuticas futuras. MÉTODOS. Se realizó un estudio descriptivo, longitudinal prospectivo, con 44 niños con diagnóstico de epilepsia focal de difícil control, ingresados en el Servicio de Neuropediatría del Hospital Pediátrico Docente Juan M Márquez, entre enero de 2003 y junio de 2007. Se realizaron estudios por electroencefalograma (EEG) al ingreso y videoelectroencefalograma, además de estudios de neuroimagen por tomografía axial o resonancia magnética nuclear. RESULTADOS. Los paroxismos en EEG involucraron el lóbulo frontal hasta en el 68 por ciento de los pacientes. En el 48 por ciento de los pacientes, los paroxismos electroencefalográficos coinciden con zonas de alteración estructural según neuroimagen, más frecuentes en el lóbulo frontal. En el 25 por ciento no hay coincidencia topográfica y en el 27 por ciento no se precisan alteraciones estructurales. CONCLUSIONES. En las epilepsias focales de difícil control se debe prestar especial atención a las zonas elocuentes con coincidencia entre el EEG y la neuroimagen, para evaluar de forma temprana las alternativas quirúrgicas de tratamiento.

Focal epilepsies are the more frequent conditions in children and a pharmacologic treatment resistance could be present up to 30 percent of patients. Aim of present paper was to direct the attention to topographic coincidence of electroencephalographic paroxysms with structural lesions by neuroimaging facilitating the future therapeutical strategies design. METHODS: A descriptive, longitudinal, prospective study was conducted in 44 children diagnosed with epilepsy of difficult control admitted in Neuropediatrics Service of Juan Manuel Marquez Teaching Children Hospital from January, 2003 to June, 2007. At admission, we made electroencephalogram (EEG) and videoelectroencephalogram (VEEG) studies as well as neuroimaging studies by axial tomography (AT) or nuclear magnetic resonance (NMR). RESULTS: Paroxysms in EEG involved frontal lobule up to the 68 percent of patients. In 48 percent, electroencephalographic paroxysms coincide with structural alteration zones according neuroimaging, more frequent in frontal lobule. In 25 percent there is not topographic coincidence, and in 27 percent there are not specified structural alterations. CONCLUSIONS: In focal epilepsies of difficult control, we must to take care of eloquent zones with coincident between EEG and neuroimaging to assess in time the surgical treatment options.

Displasias Corticais / Cortical Dysplasias

Este artigo revisa bases fisiopatológicas e classificação das displasias corticais. Enfocamos a importância do diagnóstico precoce, através dos métodos clássicos e novos. Além disso, abordamos as terapêuticas existentes e as situações em que devem ser utilizadas.

Displasias corticales como causa de epilepsia y sus representaciones en las imágenes: [revisión] / Cortical dysplasia as a cause of epilepsy and its images respresentation: [review]

Epilepsy is a chronic neurological disorder characterized by spontaneous recurrent seizures, which are clinically classified as generalized or partial. Approximately, 30 percent of patients with partial epilepsy is refractory to medical treatment. Within the refractory group we must discard the presence of cortical dysplasia as an underlying cause of the crisis. Cortical dysplasias are a type of malformations of cortical development (MCD) that are increasingly recognized as a cause of refractory epilepsy. From the radiological point of view this kind of pathology is of particular interest since imaging manifestations can be subtle or may show completely normal examinations. The aim of this paper is to review the literature, describing the imaging appearance of the normal cortical development, the classifications of cortical malformations, mainly cortical dysplasias, by highlighting the most frequent radiological signs. We also examine the current role of positron emission tomography (PET) in epilepsy, which in conjunction with magnetic resonance imaging findings and electrophysiological studies are used to define a possible surgical treatment. Through this treatment we expect to be provided with details of histopathological alterations found in the surgical specimen to be compared to the radiographic changes revealed in the pre-surgical study.

La epilepsia es una alteración neurológica crónica caracterizada por crisis convulsivas recurrentes y espontáneas, que clínicamente se clasifican como generalizadas o parciales, dentro de las cuales aproximadamente el 30 por ciento de los pacientes con epilepsia parcial son refractarios al tratamiento médico. Dentro del grupo refractario debemos descartar la presencia de una displasia cortical como causa subyacente de las crisis. Las displasias corticales son un tipo de malformaciones del desarrollo cortical que en forma cada vez más frecuente se reconocen como causante de epilepsia refractaria. Desde el punto de vista radiológico, este tipo de patología tiene especial interés debido a que las manifestaciones imaginológicas pueden ser sutiles o presentar exámenes completamente normales. El objetivo de este artículo es realizar una revisión de la literatura, describiendo el desarrollo cortical normal con su aspecto en imágenes, las clasificaciones de las malformaciones corticales y en especial de las displasias corticales, destacando los signos radiológicos más frecuentes. Además revisaremos el rol en la actualidad de la Tomografía por Emisión de Positrones (PET) en epilepsia, que en conjunto con las imágenes por resonancia magnética y los estudios electrofisiológicos se utilizan para definir un eventual tratamiento quirúrgico, el que una vez realizado nos da detalles del análisis de las alteraciones histopatológicas en la pieza quirúrgica versus las alteraciones radiológicas visualizadas en el estudio pre-quirúrgico.